Research programs at The TJL grow dramatically as the national importance of the Laboratory's research and resources increases. However, TJL's ability to grow further and contribute even more to the national scientific endeavor is limited by lack of laboratory and animal space. Research laboratories are 100 percent occupied and the Research Animal Facility (RAF) is at capacity. Yet recruitment is ongoing, particularly the search for a new Director of TJL. Laboratory and animal space must be available to recruit a scientist of the required stature. The Board of Governing Trustees recently approved a $60 million research facility expansion, the East Research Building (ERB) that will encompass laboratory and animal space. However, plans and funds for this expansion are preliminary, and it cannot meet the immediate demand. The proposed project will both alleviate the current space constraints and advance TJL's long-term expansion plans. Funds are requested to outfit shell space in the existing RAF to create two animal rooms that will be used by TJL's reproductive and developmental biology group, who will benefit from direct access to the imaging facilities and Pathology Laboratory in the Wing. A large laboratory and new personnel entry locks to the RAF will be fitted out in newly constructed shell space that is positioned to connect the existing research laboratory wings and RAF with the planned ERB. The project will also upgrade the RAF, through more effective separation of clean and dirty corridors and more efficient zoning of animal maintenance and research functions